Optical lenses are useful in a variety of industries from astronomy to telecommunications to optometry. In particular, a large international industry exists in preparing ophthalmic medical devices, such as glasses and spectacles. Fashion trends and a variety of medical conditions lead to a large variety of frames for glasses and spectacles, each requiring or utilizing a different shaped lens. To simplify the process and to improve the economy of providing lenses having a variety of prescriptions and different shapes conforming to the various frame styles available, laboratories have turned to using a set of stock lens work pieces that can be shaped in accordance with the desired frame shape and ophthalmic prescription.
To shape the stock lens work pieces to fit within a frame, an edger or other shaping machine is used to remove excess lens material and to form a contour with the stock lens work piece that conforms to the frame dimensions. In general, edgers and other shaping machines include a block or mount that secures a lens work piece during the edging or shaping process. Historically, conformable substances, such as low melting metal alloys and polymer compositions, have been used to conform to and secure a lens work piece in place. In other examples, shaping and edging equipment can include a set of blocks, each block of the set of blocks conforming to a particular curvature of an associated lens work piece. In addition, adhesives and adhesive tapes have been used to secure the lens work piece to the block.
More recently, the nature of the lens work pieces has changed with the use of more advanced materials and coatings. In particular, lens work pieces have shifted from traditional glass work pieces to polymeric work pieces, such as polycarbonate. In addition, advances have been made in coating technologies that protect lenses from scratching, prevent glare and reflection, reduce fogging, and limit dirt buildup. In particular, anti-reflection surfaces form low energy surfaces. Such low energy surfaces often are difficult to secure in a machine and, in particular, secure in a shaping or edging device that exerts large torque on the lens work piece.
As such, an improved block mounting pad would be desirable.